Pressure regulating apparatus for constant delivery pumps



NQV. 14, 1944. C, W, M01-T 2,362,713

PEEssURE EEGULATING APPARATUS PoE CONSTANT DELIVERY PUMPS Filed Dec. s1, 1945 @y PWQW- y `Patented Nom-14,

c l A) rarissima nEGULATrNG APPARATUS Fon Y coNs'rAN'r nauvnnv PUMPS` Carl W. Mott, Lav Grange, Ill., assignorjto International Harvester Com New vJersey pany, a corporation of Application December 31, 1943, serial No. 516,469

(ci. ca -52) y Y 11 oisans.

This invention has to do with a pressure regulating apparatus of a character employable in a circuit including a constant delivery pump and a motor driveable by motor propelling iluid discharged from the pump. A'I'he invention relates vmore particularly to a type ofV pressure regulating apparatus which is operable to by-pass the pumped fluid at low pressure, excepting when delivery of fluid is made into the motor, and in which apparatus there is included a control which prevents creation of the by-pass condition so long as the motor is operating.

v Heretofo're, pressure regulating apparatus has been employed for by-passing the output of a constantly driven pump at low pressure and has been operable responsively to a pressure drop in a fluid delivery passage of the apparatus, through which fluid is delivered to, the motor, to close a by-pass valve in the apparatus so that the bypass condition thereof is terminated and the iluid is'directed to the motor at high pressure, and in such apparatus the means for controlling the bypass valve has been also operable to open the bypass valve upon the occurrence of a predeterminedly high pressure in the delivery passage to the motor. Because of the entire output of the pump being directed to the motor through the delivery passage of the pressure regulating apparatus, and because of the relative non-compressibility of the iluid (usually oil) and the relative non-exrnav'nsible character of the duid delivery passage, said predetermined pressure increase occurs very quickly when the motor is allowed to operate at slow speed. Likewise, because of the aforesaid character of the fluid and of the fluid delivery passage, the pressure of predetermined' maximum amount upon being attained, and the by-pass condition established, is very quickly dissipated so that the eiect, when the motor is operated slowly, has been for a rapid succession of by-pass and noni-by-pass conditions of the ap` paratus occurring at an audible frequency, setting up a chattering noise in the apparatus.

The primary' object of the present invention is the provision of an auxiliary control means for the by-pas's valve o! such apparatus for precluding the opening lolf such valve irrespective ofthe magnitude of the pressure attained in the iluid delivery passage when thevmotor is operated.

A more specic object of the invention is the utilization of a control value means having counterparts either of ywhichis operable to cause the by-pass valve to remain in the closed position, and the 'further utilization of a control means having counterparts for respectively operating the control valve means counterparts, whereby one of the valve counterparts is controlled to cause closing of the byhpass valve in response vto a 'drop in pressure in the iluid delivery `passage of the apparatus and whereby the other valve counterpart is controlled to cause the by-pass valve to remain: closed so long as the motor is operating.

A further object of the invention is the provision of means subjected to the discharge of iiuid expended from the motor for operating the valve counterpart which is controlled by the opc.

eration of the motor. .s

These and other desirable objects inherent in and encompassed by the invention will become more readily apparent from the ensuing description when read-in commotion with the single gure of drawing annexed hereto andA which shows in section an apparatus embodying a preferred form o! the invention, together with diagrammatic symbols illustrating the connections therewith of a constant delivery pump, a iluid driven motor, a valve controlling the admittance of fluid to the motor. and a reservoir.

With continued reference to the' drawing,gthe casingfor the apparatus can be seen to consist of a laminated structure including a group of superposed plates designated II to I6. These plates are suitably apertured for the reception or bolts as I1 for holding the plates in assembly. Fluid is delivered to an inlet channel I8 von the apparatus from a constant delivery pump I9, and

when an admittance valve 2I is opened. the iluid entering the channel I8 can flow past a check .valve4 22 into a delivery channel 23 and thence through said valve 2| to the motor M. Pursuant .to operation of the motor M, fiuidis discharged or expended from an exhaust portion thereof into -ailuid return passage 24 or the apparatus. Fluid for the pump' I9 is obtained from a reservoir 25 and the iluid is replenished to the reservoir 25,

from a by-pass passage 26 in the apparatus. Various passages and channels are formed in the casing by means of holes through certainiot theplates and open channels in opposed faces of the plates which when placed in abutting relation convert these channels into buried channels. The receiving passage I8, for example, includes holes 21 and 2l in the plates I5 and I4, and a'channel 2l in the underface of the plate Il. The delivery passage includes a channel SI in the upper face 4oi? plate I2, holes I2 and 33 in-the plates and I4, channel 3l in plate I4and a hole l5, in the plate. I5. The by.pass passage includes a chan..

nel It in the upper face of the plate I2, holes I'I the plate I8, and a hole 4| in said plate I8.

The aforesaid check valve 22 includes a ball 42 urged onto a seat 48 therefor formed within a hole 44 in the plate I8. Seating means for the bali 42 includes a hea-ded follower member 48. and a spring 48, both disposed within a hole 41 in the plate I2. A by-pass valve 48, for controlling communication between the inlet passage I8 and the by-pass passage 28, includes a ball 48 forcibly pressibly onto a seat 8| therefor, formed within a hole 82 in the plate I8. Fluid actuated means forv forcibly pressing, the ball 48 onto the seat 8| includes a cup-like piston 88 slidable within a cylinder bore 84 formed as a hole inthe plate I2. A spring cup 88 serving as a`follower for the ball 48 is slidablewithin the piston 88 where said spring cup is inverted over a spring 88. Fluid pressure incurred in the cylinder bore 84, beneath the piston 88, raisesthe same together with the spring and follower therein for seating the ball 48. A pressure transfer passage 81, for supplying the fluid pressure beneath the iston 88, is obtained in a manner presently des bed from the inlet passage I8 and includes a'limited Yflow caaseavis includes chamberl! formed within casing plates I8 and I8. The upper end of this chamber 82 communicates with the fluidv delivery passage 28 through a passage 88, consisting of channels .84, 88, and '88 in the plates I8 and I8. A cylindrical cup 81 within the chamber 82 contains a piston 88 connected -with a stem 88, extending downwardly through a vhole 8| in the bottom of the cup 81 and through -a hole 82 in the plate I8, into pacity hole 88 in the plate I8, a limited flow cal pacity hole 89, and a channel 8| in the plateI I. Excepting when iluid is allowed to escape from the pressure transfer passage 81, said passage will cause -an equalization of pressure in the hole 82 above the by-pass ball 88 and in the space in the bore 84,-beneath the piston 88, and since the area of the lower end of the piston 88 exceeds the transverse area of the hole 82. the composite force exerted upwardly on the piston will exceed that exerted downwardly on the ball 48 with the result that said ball will-be held positively seated irrespective of the magnitude of pressure occurring in the inlet passage I8.

A control passage for diverting uid from the pressure transfer passage 81 is designated 82. This control passage 'includes a hole 88 in the plate I 8, a channel 84 inthe plate I4, a second hole, 88, in the plate I8, a channel 88 in the plate I2, a third hole, 81, in the plate I8, an axial bore 88 in asleeve 88, a valve port 1|, and a countersunk portion 12 of a hole 18, in which said sleeve 88 is disposed. Control valve means consisting of two counterparts are employed for controlling the escape of fluid from the transfer passage 81,

through the control passage 82, into the by-pass passage 28. One of these control valve counter- -parts `is designated 14 and includes `a. ball 18 urged onto a seat 18 therefor formed in the hole 88 by means of a spring 11 acting upon a ball follower 18. When the ball 18 is upon the seat l18, the hole 88 will be closed, preventing. the escape of fluid from the pressure transfer passage 81. The other control valve counterpart includes the aforesaid sleeve 88 and a plunger 18 slidable axially therein into and from closing relation with the port 1| in said sleeve. When the plunger 18 is lowered from the'position shown in the ldrawing, intoclosing relation with the port 1|, lthis control valve counterpart 88'-18 will beeifective for preventing the escape of fluid from the pressure transfer passage 81, just as effectively as they .livery vpassage 28. Said valve control means isgenerally designated 8|. This control means 8| a recess 88 in the plate I4. The lowerend of the stem has a reduced diameter portion 84 which projectsthrough a hole 88 in the plate I4 into hole 88 of plate I8 for forcing the vvalve ball 18 downwardly into the unseated position shown when the piston 88 and the stem 88 are lowered by Vthe existence of a sufiicient fluid pressure.in the chamber. 82 above the piston 88. When the valve member 18 is in the elevated position (shown) for uncovering the port 1|, uid can enter the recess 88 at the lower end of -the large diameter portion of the stem 88 and can be exhausted therefrom freely through a breather hole 88. v

Control meansI for the control valve means counterpart 88-18 takes the form of a cup-like piston member 81 contained slidably within a cylindrical portion 88 of the return passage 24v formedin the plate I8. This piston member 81 has diametrically opposed circumferentially extending sidewall openings 88 and a small breather opening I8| in its ttom. output of the motor M is discharged into the return passage 24 so that, while the motor is operating .even at minimum speed, there will be sumcient discharge of fluid into the return passage 24 for forcing the piston 81 downwardly sufficiently far to place the stem 18 in covering relation with the port 1| to insure that no fluid shall escape from the pressure transfer passage 81. Substantially concurrently with the piston 18 moving downwardly farenough to place the stem 18 o'ver the port 1|, said sidewall openings 88 of the piston will be projected into communication with the vley-pass passage 28. Said sidewall openings 88, when projected entirely into the by-pass passage, have a combined flow capacity adequate to conduct lthe nuid discharge from the motor M without materially impeding its operating speed.

Assurance that undesirably high pressures shall be avoided in the apparatus is provided for by a pressure relief valve |82 which consists of a bail |88, urged against a seat |84 in an opening |88 of the plate I8 by a spring |88, which acts upwardly upon a spring cup follower |81 which is slidable within a hole |88 in the plate I2. s

Operation of `the apparatus The' apparatus is shown in the drawing with its parts in their respective positions for establishing the by-pass condition. Such by-pass condition is incurred by fluid at high pressure trapped in the uid delivery passage 28, between the admittance valve 2| for the motor M and the check valve 22. motorM, the admittance valve 2| is closed and (the uid deliveryinto the inlet passage I8, from the constant delivery pump I8, continues to ow past the check' valve 22 until the fluid pressurein the delivery passage 28 attains such a predetermined maximum that it is effective through the fluid column in the control passage 88 to de,- velop suillcient uid pressure in the chamber 82 for pressing the piston 88 downwardly against thepforce of the spring 88a for opening the control valve 14, concurrently with the closing of The entire exhaust" Upon the stopping of the the valve 2| and the stopping oi the motor M. the uuid ceases to be discharged from the motor .into the return passage 24, whereby fluidy in the passage 51, through the control passage 82, past' the valve 14 and the valve Sil-19, through the port 1| and into the by-pass passage 29 from which it is discharged into thevreservoir 25. This escape of iluid, through the control passage 82 from the discharge pressure transfer passage 51, incurs a unit pressure beneath the by-pass valve closing piston 53 less than the pressure inthe inlet passage 29 above the by-pass valve ball 49. This pressure differential is caused to obtain, because the ow capacity of the control passage 62 exceeds the ow capacity of the small bore or ho1e58 in the pressure transfer passage 51. Consequently, the predominatlng pressure above the ball t9 opens the by-pass valve 48 and permits the iiuid to escape from the inlet passage i8 into the by-pass passage 26, so that the fluid from the constant delivery motor can be 'circulated freely at low pressure.

When it is desired to cause the motor M to be driven, the apparatus will function automatically, upon the opening of the admittance valve 2|, to terminate the by-pass condition and deliver fluid at high pressure into the delivery passage 23 for actuating the motor. Opening olf the admittance valve 2|, and the ensuing initial movement of the work member of the motor M, will instantaneously cause a slight reduction of the pressure in the delivery passage 2t, and this pressure reduction by virtue of the communicative passage 83 with the controlmeans chamber 82 causes a. corresponding pressure diminution in such chamber, permitting the piston 88 to be elevated by the spring 88a for closing the controlv valve' 1t, thus the control passage 82 is blocked so that thev pressure transfer ,passage 5i conducts iiuid from the inlet passage il to the bore 54, beneath the by-pass valve operating pismotor M,l which is moving at the slow speed, and because of the relative noncompressibility of the fluid in said delivery passage and the relative nonexpansible chara'cterof the Walls of this delivery passage, the slow delivery of iluid through the admittance valve 2| would be effective for instantaneously lowering the pressure in the delivery passage 28 and, hence, inthe chamber 82 for permitting the piston 88 to rise, and close the controlpvalve 14 for again establishing the closed condition of the by-pass valve 48 for ter- `minating the by-pass condition of the apparatus. Thus, while the admittance valve 2| would-be but partially opened to take but part oi.' the output of the constant'delivery pump I9 when it is desired to operate the motor M ata slow speed, an operating condition would prevail in which the control valve counterpart 14 and the by pass valve,48 would be rapidly opened and closed.

This rapid opening and closing of the valve 14 and 48 is undesirable because of undue wear of their balls and ball seats, and also because of a chattering noise thereby incurred.

The aforesaid vacillations of the valves 14 and 48 is prevented by the important improvement constituted bythe cooperating pressure relief .valve |02 and the control valve counterpart 68-19. During operation of the motor M at anygspeed, fluid is expended from its exhaust into the return vport 24, whereby the cup-like oiston member 91 together with the 'valve stem 19 is forced downwardly causing said Avalve stem to close the port 1| in the control passage 62.

, Piston member 91 moves downwardly far enough ton 53, for raising this piston to close the byf pass valve d.

lNow with the by-pass valve closed, the entire output or the pump i9 must escape from the in- ,let passage i8, past the check valve 22 to motor M, providing the admittance valve 2i is opened sunlciently far to pass the entire pump output, or through the pressure relief valve |02vinto the by-pass passage Mt. The spring itt of the pressure relief valve |02 is suiilciently strong to preventl opening of this valve, excepting under ab for opposed'openings 99 in the sidewalls to register with the channel 39 which is a constituent of the by-pass passage 26, whereby the motor exhaust is directed into the by-pass passage for ultimate discharge into the reservoir 25. With the port 1I closed by the valve stem 19 and upon the pressure in .the delivery passage 23 attaining the aforesaid maximum for forcing the piston 88 downwardly for opening' the control valve counterpart 14, the by-pass valve 48 will be unaffected, since the control passage 62 will remain `blocked to prevent the escape of fluid from beneath the actuatingA means` piston 53 for .the bypass valve. Slow operation of the motor M by a partial opening of the admittance valve 2| will 60 thus be caused to -incur a somewhat abnormal 65 fluid to escape through the hole normally high pressure in the receiving cham- Y ber i8. Therefore, before the pressure relief valve B02 opens, assumingthe admittance valve 2i to be but partially opened to cause the motor to be driven atslow speed, a predetermined maximum pressure' will be attainedin the delivery passage 23 and transmitted through thepassage @t for forcing the piston 88 downwardly to open the controlvalve 14. Assuming for the moment that` the control valve counterpart 89-19 were not' present, this opening lof the valve 14 would clear the control passage 82 for bleeding i'luid from the pressure transfer passage 5l for open,- ing the lay-pass valve 4t. Delivery from the receiving passage I8 into the delivery passage 28 would' immediately cease, but since the valve 2| high pressure in thepassages I8 and 23, but the pressure relief valve |02 is adjusted for opening prior to the attainment of dangerously high pressure in these passages, and thereby allowing the E05 into Athe byv pass passagev ,26.

It will be seen, therefore, that during the periv ods when the motor M is operated at slow speeds, the excess delivery of Vthe constant delivery w pump is by-passed through the pressure relief e5 Upon the closing of the admittance valve '0 pressure had not already been at this magnitude.

Discharge from the pump will then occur -or continue past the pressure relief valve |02 into the by-pass'passage 26, and the pressure of iiuid in the inlet passage I8 will be transmitted through would vremain open for delivering duid to the?! the small bore or hole 58 in the pressure transferv 4. passage 51, past the control valve counterpart 14 and into the control'passage "for urging the valve stem 19 and the piston 91 upwardly. With i 'the motor stopped and iluid no longer being discharged into the return passage 2l, the upward force of the fluid upon the lower end of the valvey stem 'Il will cause the piston 91' to rise on exases,

pelling fluid from theI breather hole lill, and when the valve stem 19, and piston 91 having been raised suillciently to uncover the port 1I, fluid can escape from the; pressure transfer passage 61 through the control passage I2 for caus- Aingthe by-pass valve 48 to open and reestablish the by-pass condition of the apparatus.

It was explained above how the control valve counterpart 89-19 when closing the port 1l is thereby effective for preventing escape from the pressure transfer passage i1 and for thereby preventing establishment of the by-passcondition of theapparatus even though the control valve .counterpart 'M should be opened. -,It should be noted;y however, that ,with a suillciently strong spring 88a in the control means for said control valve counterpart 'Il and with thelower end of the large diameter portion of the valve stem 89 in the recesses 93 of suihciently large area with respect to the upper-end face of the piston B8, the iluid retainedwithin the control passage 62 (and in the recess 93 and the-breather hole 96) between the valve 69-19 and the spring pressed' ball 15 of the valve 14, will be effective for preventing downward displacement of the valve stem arating said inlet passage from the `by-p'ass passage and operable, when closed, to incur sufficient build-up of pressure in' the inlet passage for opening the check valve and discharging to the motor through said delivery passage, by-pass valve closing means capable of disablement to /cause the by-pass valve to open, disabling means responsive to a predetermined increase of pressure in said delivery passage for disabling the by-pass valve closing means, means responsive to iluid discharge from the motor to contravene the disabling function of said disabling means,

' Vand a. pressure relief valve disposed to relieve` imid from said inlet passage in the prevention of excessive pressure therein.

2. In a pressure regulating apparatus employ/f able in a circulatory system between .a constant delivery pump and a. fluid-driven motor'drivable by fluid discharged from said pump; a delivery passage communicative with said motor to conduct propelling uid thereto from the pump at. high pressure', a by-pass passage communicative` With said delivery passage to by-pass'the -uid therefrom about the motor at low pressure, a bypass valve opena'ble to create said communication of the by-pass passage and closable to terminate the same, means operable responsively to a decrease in the pressure in said delivery passage to close said by-passvalve,-and means-responsive to the prevailing operation of said motor to preclude the opening of said by-paSS valve.

3. In a pressure regulating apparatus for'the propelling fluid of a uuid-driven motor: a delivery passage through which'fluld is delivered to the motor, a by-pass passage, a by-pass valve operable to introduce the uld into the by-pass pass sage divertively of said delivery passage and,

closable to preclude such introduction of fluid into the by-pass passage, valve closing means subjectable to the pressure of said uid for actuation to close said by-pass valve, control valve means operable responslvely to a predetermined decrease of pressure in said deliveryipassage to subject the valve closing means tothe pressure of said fluid as aforesaid for actuating the same, and means responsive to the operation of said'motor to preclude theopening of said by-pass valve while the motor is being driven.

4. In a pressure regulating apparatus for the propelling fluid oi' a fluid-driven motor; a delivery passage through which fluid is delivered to the motor excepting when diverted from said delivery passage, a by-pass passage, a by-pass valve operable to introduce theiluid into said by-pass passage divertively of said delivery passage and closable'to preclude such introduction of the uld into said by-pass passage, valve closing means actuable to close the by-pass valve, control means operable responsively to a decrease of pressure in said delivery passage to incur the actuation of lsaid valve closing means, and means responsive to the operation of said motor to preclude opening of the by-pass valve while the motor is being driven.

5. The combmetion set forth in claim 4, wherein said means responsive to the operation of .the motor serves to maintain the valve closing meansactuated during operation of the motor.

6. In a pressure regulating apparatus for the propelling fluid of a duid-driven motor having an exhaust through which fluid is expended during its operation; a delivery passage .through which uid is delivered to the motor, a by-pass passage, a by-pass valve operable to introduce the fluid into the by-pa'ss passage divertively of said delivery passage and closable to preclude such introduction. of fluid into the bypass passage, valve closing means subjectable to the pressure of said iluid for actuation to close said by-pass valve, control valve means operable responsively to a predetermined decrease `of pressure in said delivery passage to subject the valve closing means to the pressure of said fluid as' aforesaid for actuating the same, and .means operable by the expended uid to maintain said valve closing means subjected to the iluid pressure for actuating the same,

7. In a pressure regulating apparatus for the propelling iluid of a fluid-driven Amotor having an exhaust through which iluid is expended during its operation; a receiving passage for the reception of such fluid, a delivery passage through which thefluld is delivered from said receiving passage to the motor, a return passage for the fluid expended from the motor, a by-pass passage, a by-pass valve operable-to direct the receiving passage iluid into the byi pass passage divertively of the delivery passage and closable to direct the receiving passage fluid into the delivery passage, valve operating means for said by-pass valve, control means operable responsively to a decrease of pressure in saidl delivery passage to cause said operating means to close said by-pass valve, and means operable by the expending of uid into said return passage for precluding opening of the by-pass valve.

8. 'I'he combination set forth in claim 7, Wherein said means responsive to the expending of fluid into the return passage controls said valve operating means to maintain the by-pass valve `closed during such expending of fluid.

9. In a pressure regulating apparatus for the propelling fluid of a uid-driven motor having an exhaust through which iluid is expended during its operation; a receiving passage for the reception of such fluid, a delivery passage receiving passage, control valve means operable to subject said valve operating means to said receiving passage pressure, and control means operable responsively to a decrease of pressure in said delivery passage for so operating the control valve means and operable responsively to the expanding of uid into said return passage for maintaining the control valve means in an operated condition so .long as iiuid is expended into the return passage irrespective of subsequent uctuations in the delivery passage pressure.

10. In a pressure regulating apparatus for the propelling uid of a fluid-driven motor having an exhaust through which uid is expended during its operation; a receiving passage for the re-v ception of such fluid, a delivery passage through which the uid is delivered from said receiving passage to the motor, a return passage for the uid expended from the motor, a by'pass passage, a'by-pass valve operable to direct the receiving passage fluid into the by-pass passage divertively of the delivery passage and closable to direct the receiving passage fluid into the delivery passage, valve operating means forsaid by-pass valve, said valve operating means being operable to close the by-pass valve when subjected to the pressure of the uid in said receiving passage, control valve means including counterparts of which either is operable to subject said valve operating means to the receiving passage pressure, and control means comprising counterparts of which one is operable responsively to a decrease of pressure in the delivery passage for so operating one of the control valve counterparts and of which control means counterparts the other is operable responsively to the expending of fluid into the return passage for so operating the other of the control valve counterparts.

, .11. In a pressure regulating apparatus emplo able in a system utilizing a constant delivery pump for causing periodic movement of a uid column; a uid inlet passage'for connection with the pump discharge, a iiuid delivery passage for the issuance of said iiuid column, a check valve separating said fluid delivery` passage from said inlet passage, a by-pass passage, a by-pass valve separating said inlet passage from the by-pass passage and operable, when closed, to incur sufiicient build-up of pressure in the inlet passage for opening the check valve and discharging through said delivery passage to move said column, by-pass valve closing means capable of dis` ablement to cause the by-pass valve to open, disabling means responsive to a predetermined increase of pressure in said delivery passage for disabling the bil-pass valve closing means, means responsive to the movement of said fluid column to contravene the disabling function of said disabling means, and a pressure relief valve disposed to relieve iiuid from said inlet passage in the prevention of excessive pressure therein.

CARL W. MOTT. 

